Polydopamine-Coated Alginate Microgels: Process Optimization and In Vitro Validation

Abstract

In the last decade, alginate-based microgels have gained relevant interest as three-dimensional analogues of extracellular matrix, being able to support cell growth and functions. In this study, core-shell microgels were fabricated by self-polymerization of dopamine (DA) molecules under mild oxidation and in situ precipitation of polydopamine (PDA) onto alginate microbeads, processed by electro fluid dynamic atomization. Morphological (optical, SEM) and chemical analyses (ATR-FTIR, XPS) confirmed the presence of PDA macromolecules, distributed onto the microgel surface. Nanoindentation tests also indicated that the PDA coating can influence the biomechanical properties of the microgel surfaces—i.e., σmaxALG = 0.45 mN vs. σmaxALG@PDA = 0.30 mN—thus improving the interface with hMSCs as confirmed by in vitro tests; in particular, protein adsorption and viability tests show a significant increase in adhesion and cell proliferation, strictly related to the presence of PDA. Hence, we concluded that PDA coating contributes to the formation of a friendly interface able to efficiently support cells’ activities. In this perspective, core-shell microgels may be suggested as a novel symmetric 3D model to study in vitro cell interactions.

Designing Advanced Drug Delivery Systems: Core-Shell Alginate Particles through Electro-Fluid Dynamic Atomization

“…Viscosity (η, Pa•s) and viscoelastic properties play a crucial role in the EFDA to process the polymer solutions, affecting the morphology of microparticles [34]. For instance, the higher viscosity of solutions generates larger and spherical microparticles, while lower viscosities generate smaller particles [35].…”

“…After collecting particles, they were observed using a confocal microscope. Additionally, core/shell circularity of microgels was evaluated according to previous studies [ 34 ] using a customized image analysis procedure—i.e., adjustment of the image threshold to remark the core/shell interface and measurement of the shape factor of the inner core/outer shell using the following equation: C = 4π(A/P 2 ) where A is the area, and P is the perimeter. For an ideal sphere, C = 1.…”

Optimization of Polyvinyl Alcohol-Based Electrospun Fibers with Bioactive or Electroconductive Phases for Tissue-Engineered Scaffolds

“…Recent studies have focused on the idea that regenerative processes can be supported and accelerated by electrical stimuli which can facilitate the repair of the injured tissues [40]. For this purpose, the use of intrinsically electroconductive polymers is rapidly growing for different biomedical applications, from medicine to biosensing [49,50,88]. In this view, the fabrication of PVA fibers by integrating material phases with different electroconductive properties was preliminarily investigated (i.e., PVP and PEDOT:PS) (Figure 6).…”

“…In this view, incorporating electroactive phases-i.e., conductive polymers (CPs)-into PVA fibers can be a promising strategy to support the electroconductive mechanisms that regulate cellular adhesion and proliferation. To date, various CPs such as polypyrrole (PPy), poly(3,4-ethylene dioxythiophene) (PEDOT, conductivity up to 10 3 S/cm [44]), and polyaniline (PANi) were found to be particularly suitable for biomedical use [45][46][47] and electrospinning was successfully employed for the manufacture of composite or blended fibers based on CPs [48][49][50]. Moreover, polyvinylpyrrolidone (PVP) has been studied before in order to improve the conductive properties of PVA as polymer coatings around 0.30 S/cm [51] and there are studies reported in the literature that focused on the effects of CPs to promote the regeneration of electroactive tissues (i.e., muscles, nerves, brain) [52].…”

Optimization of PVDF-TrFE Based Electro-Conductive Nanofibers: Morphology and In Vitro Response

“…This makes them suitable for a wide range of applications in fields such as electronics, energy storage, and sensing [1][2][3]. In this context, research efforts have focused on exploring the properties and potential of various electroconductive polymeric composites and developing new methods for their synthesis and characterization for biomedical use [4][5][6][7].…”